Flex坐标

  flash和flex针对不同的目的,提供了3种不同的坐标系。

          全局的就是(stage级别的)

          本地坐标系(组件级别的)

          内容坐标系(相对于本地坐标系说的)

    这些坐标系的点是可以转换的,并且有相应的方法,看来adobe想得挺周到。我们一个一个的说一下:

    全局

           这个坐标系的原点在整个flash舞台的左上角,MouseEvent实例的stageX,stageY就是这个坐标系中的值。

    本地

        坐标原点是相对的组件的左上角,MouseEvent中的localX,localY就是相对这个坐标系说的。

    内容

        这个东西比较抽象了UIComponent类实例的contentMouseX  和 contentMouseY 就是了,这个主要针对有滚动条的组件说的,有滚动条了,内容肯定不少,内容所占的区域的坐标就是这个坐标系了。

下面有个官方的图说明了三个坐标系的关系及位置:

坐标转换还有现成的方法:

contentMouseX

返回mouse的内容坐标x值

contentMouseY

返回mouse的内容坐标Y值

contentToGlobal   

将内容坐标转换成全局坐标

contentToLocal 

将内容坐标转换成内容坐标

globalToContent   

将全局的转成内容坐标

globalToLocal 

全局的转成本地的

localToContent

本地到内容坐标

localToGlobal 

本地到全局坐标

下面是一个小例子:

<?xml version="1.0"?>  
<!-- containers\intro\MousePosition.mxml -->  
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"  
    backgroundColor="white">  
     
    <mx:Script>  
        <![CDATA[  
          import mx.controls.Alert;  
          // Handle the mouseDown event generated  
          // by clicking in the application.  
          private function handleMouseDown(event:MouseEvent):void {  
                 
            // Convert the mouse position to global coordinates.  
            // The localX and localY properties of the mouse event contain  
            // the coordinates at which the event occurred relative to the  
            // event target, typically one of the  
            // colored internal Canvas controls.  
            // A production version of this example could use the stageX  
            // and stageY properties, which use the global coordinates,  
            // and avoid this step.  
            // This example uses the localX and localY properties only to  
            // illustrate conversion between different frames of reference.  
            var pt:Point = new Point(event.localX, event.localY);  
            pt = event.target.localToGlobal(pt);  
                 
            // Convert the global coordinates to the content coordinates  
            // inside the outer c1 Canvas control.  
            pt = c1.globalToContent(pt);  
                
            // Figure out which quadrant was clicked.  
            var whichColor:String = "border area";  
               
            if (pt.x < 150) {  
                if (pt.y < 150)  
                    whichColor = "red";  
                else  
                    whichColor = "blue";  
            }  
            else {  
                if (pt.y < 150)  
                    whichColor = "green";  
                else  
                    whichColor = "magenta";  
            }  
                 
            Alert.show("You clicked on the " + whichColor);  
          }  
        ]]>  
    </mx:Script>  
    <!-- Canvas container with four child Canvas containers -->  
    <mx:Canvas id="c1"  
        borderStyle="none"  
        width="300" height="300"  
        mouseDown="handleMouseDown(event);">  
         
        <mx:Canvas  
            width="150" height="150"  
            x="0" y="0"  
            backgroundColor="red">  
            <mx:Button label="I'm in Red"/>  
        </mx:Canvas>  
        <mx:Canvas  
            width="150" height="150"  
            x="150" y="0"  
            backgroundColor="green">  
            <mx:Button label="I'm in Green"/>  
        </mx:Canvas>  
        <mx:Canvas  
            width="150" height="150"  
            x="0" y="150"  
            backgroundColor="blue">  
            <mx:Button label="I'm in Blue"/>  
        </mx:Canvas>  
        <mx:Canvas  
            width="150" height="150"  
            x="150" y="150"  
            backgroundColor="magenta">  
            <mx:Button label="I'm in Magenta"/>  
        </mx:Canvas>  
    </mx:Canvas>  
</mx:Application> 

 

posted @ 2013-10-31 14:11  牧之丨  阅读(432)  评论(0编辑  收藏  举报